Yamaha 01X - Manual (Page 122)

Before Using
Basics Section
Appendix
Getting Started
Reference
122
01X Owner’s Manual
Parameter Lists
Explanations for Dynamics Parameters
● Compressor (CMP) parameters:
Threshold (THRESH) determines the level of input signal
required to trigger the compressor. Signals at a level below the
threshold pass through unaffected. Signals at and above the
threshold level are compressed by the amount specified using
the Ratio parameter.
Ratio controls the amount of compression — the change in out-
put signal level relative to change in input signal level. With a 2:1
ratio, for example, a 10 dB change in input level (above the
threshold) results in a 5 dB change in output level. For a 5:1
ratio, a 10 dB change in input level (above the threshold) results
in a 2 dB change in output level.
Attack controls how soon the signal is compressed once the
compressor has been triggered. With a fast attack time, the sig-
nal is compressed almost immediately. With a slow attack time,
the initial transient of a sound passes through unaffected.
Release determines how soon the compressor returns to its
normal gain once the trigger signal level drops below the thresh-
old. If the release time is too short, the gain will recover too
quickly causing level pumping — noticeable gain fluctuations. If
it is set too long, the compressor may not have time to recover
before the next high level signal appears, and it will be com-
pressed incorrectly.
Out Gain (GAIN) sets the compressor’s output signal level.
Compression tends to reduce the average signal level. Out Gain
can be used to counter this level reduction and set an appropri-
ate level for the next stage in the audio path.
Knee sets the transition of the signal at the threshold. With a
hard knee, the transition between uncompressed and com-
pressed signal is immediate. With the softest knee, knee5, the
transition starts before the signal reaches the threshold and
gradually ends above the threshold.
Compressor
-70
-60
-50
-40
-30
-20
-10
0
+10
+20
-70 -50 -30 -10 0 +10 +20
Input Level
Output Level
dB
dB
Knee = hard
Threshold = -20dB
Compression ratio = 2:1
-60 -40 -20
A compressor provides a form of automatic level control. By attenuating high
levels, thus effectively reducing the dynamic range, the compressor makes it
much easier to control signals and set appropriate fader levels. Reducing the
dynamic range also means that recording levels can be set higher, therefore
improving the signal-to-noise performance.
Expander
-70
-60
-50
-40
-30
-20
-10
0
+10
+20
-70 -50 -30 -10 0 +10 +20
Input Level
Output Level
dB
dB
Threshold = -10dB
Knee = hard
Expansion ratio = 2:1
-60 -40 -20
-70
-60
-50
-40
-30
-20
-10
0
+10
+20
-70 -50 -30 -10 0 +10 +20
Input Level
Output Level
dB
dB
Threshold = -20dB
Knee = knee5
Expansion ratio = 2:1
-60 -40 -20
An expander is another form of automatic level control. By attenuating the signal below the threshold, the expander
reduces low-level noise and effectively increases the dynamic range of the recorded material.